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The human body constantly produces thermal electromagnetic radiation with a maximum of about 10 µm. This thermal radiation has a number of positive effects on the human body and, in addition, allows the insulation under clothing to be improved under extreme climatic conditions, causing a significant reduction in ambient temperature. With so-called far-infrared (FIR) textiles, it is possible to ensure the reflection of thermal radiation back to the human body. In the first part of this review, the generation of heat by the human body and its propagation by radiation through the skin are comprehensively explained. The thermal characteristics of the individual skin layers as an emitter of infrared radiation are given. The second part discusses the basic preparation methods of FIR textiles. Suitable particle systems are described based on metals and their oxides, porous carbon, and special ceramics. Modification of the fiber phase (especially the fineness of the fibers and the porosity of the fabric) in combination with the surface coating of metals is also used for their health-promoting effects. The main manufacturers of FIR textiles and their typical products are mentioned.

The production of three-layered cement-bonded particleboards (CBPB) differs in most cases from that of adhesively bonded particleboards. However, one production step is quite similar: mat forming. A homogeneous mat is formed by aerodynamic or by mechanical spreading or by a combination of both methods. The distribution of the particles is influenced by their separation and flight characteristics. Those characteristics are in turn influenced by particle size and the combination of the particle’s surface area and weight. Because density of cement is higher than that of wood, the cement/wood (c/w) ratio will influence the particles’ separation and flight characteristics significantly. In the current study, laboratory-made particles of different sizes were mixed with different amounts of cement. An aerodynamic former was then used to help determine the influence of the different particle types and the c/w ratio of the mix on mat forming. The strewn particles were analysed for their distribution of mass, size and cement content as a function of spreading distance. The particle size decreased with increasing spreading distance. In addition, the cement content and spreading distance were positively correlated. For a c/w ratio of 1.9, increasing cement content correlated with increasing distance. This means, large particles and less cement tended to fall earlier than smaller ones and more cement. This corresponds to the observation that the specific surface area of the particles increases with increasing spreading distance. Vice versa, the density of the particles decreases with increasing spreading distance. The effect is more apparent when the particle mixture is heterogeneous in size at constant process parameters (e.g., air velocity). Looking at the density profile of a CBPB board, the surface layers consist of small particles with a higher cement fraction, and the core layer consists of large particles with smaller cement fraction. Thus, the production of CBPB requires two aerodynamic formers working in opposite directions. With the results of this study, it is possible to optimise production parameters, such as the speed of the transport caul and the air velocity with regard to the infeed raw material parameters in order to create a symmetrical particle distribution from top to bottom of the mat, resulting in an optimized and application-oriented density profile.

This work examines the effect of thermal modification temperatures in the production of thermally modified wood on the cutting and fracture parameters when cutting heat-treated spruce wood by a circular sawblade machine. The samples were thermally modified at 160, 180, 200, and 220 °C. One sample was unmodified and was used as a reference sample. On the basis of the performed experiments, the fracture parameters (fracture toughness and shear yield strength) were calculated for the axial–perpendicular direction of cutting. In comparison with the theoretical assumptions, the influence of temperature on the cutting and fracture parameters was confirmed. Thermally treated wood is characterized by increased fragility and susceptibility to crack formation, as well as reduced density, bending strength, and shear strength. These properties significantly affect the size of the cutting force and feed force, as well as the fracture parameters. As the temperature increases, the values of these parameters decrease. The mentioned material characteristics could be useful for the optimization of the cutting process, as well as for the issue of energy consumption during the machining of heat-treated wood.

Cutting tools have long been coated with an AlCrN hard coating system that has good mechanical and tribological qualities. Boron (B) and vanadium (V) additions to AlCrN coatings were studied for their mechanical and tribological properties. Cathodic multi-arc evaporation was used to successfully manufacture the AlCrBN and AlCrVN coatings. These multicomponent coatings were applied to the untreated and plasma-nitrided surfaces of HS6-5-2 and H13 steels, respectively. Nanoindentation and Vickers micro-hardness tests were used to assess the mechanical properties of the materials. Ball-on-flat wear tests with WC-Co balls as counterparts were used to assess the friction-wear capabilities. Nanoindentation tests demonstrated that AlCrBN coating has a higher hardness (HIT 40.9 GPa) than AlCrVN coating (39.3 GPa). Steels’ wear resistance was significantly increased by a hybrid treatment that included plasma nitriding and hard coatings. The wear volume was 3% better for the AlCrBN coating than for the AlCrVN coating on H13 nitrided steel, decreasing by 89% compared to the untreated material. For HS6-5-2 steel, the wear volume was almost the same for both coatings but decreased by 77% compared to the untreated material. Boron addition significantly improved the mechanical, tribological, and adhesive capabilities of the AlCrN coating. © 2021 by the authors. Licensee MDPI, Basel, Switzerland., Department of Mechanical Engineering, University of Defence in Brno [SV20-216]; Project for the Development of the Organization "DZRO Military autonomous and robotic systems"; Slovak Research and Development AgencySlovak Research and Development Agency [APVV-15-0710], Agentúra na Podporu Výskumu a Vývoja, APVV: APVV-15-0710

Lowland oak forests host high biodiversity throughout Europe, and to maintain their high biodiversity potential we need to understand how current silviculture practices influence these ecosystems. The most common harvest approach in oak woodlands remains clear-cutting followed by site preparation for reforestation. The site preparation can vary in intensity and possibly affect forest biodiversity in various ways. We studied the impact of site preparation intensity on ground-dwelling arthropod predators and detritivores in commercial oak woodlands. The intensive management included mechanical site preparation with soil milling, stump removal, and herbicide application. The extensive management consisted of natural succession after reforestation with only such slight disturbances as regular hand-provided mowing of vegetation. We recorded 120 spider species, 92 species of ground beetles, 10 species of centipedes, 17 species of millipedes, and 7 species of woodlice, including a relatively large number of threatened species. We found that intensive post-logging management strongly homogenized the habitat structure, and this led to low multi-trophic taxonomic and functional diversity in comparison to that under extensive management. At sites with extensive management, there was not only high functional diversity but also high functional redundancy. Species of conservation concern almost vanished from clearings under intensive management. The high multi-trophic diversity and functional redundancy indicate that extensive site preparation may enhance ecosystem multi-functionality, including primary productivity and ecosystem resilience. Extensive post-harvest management is therefore strongly preferable, and it is also economically more feasible. Intensive post-harvest management should be prohibited in lowland forests within transition zones to localities under nature protection or in natural oak forests.

There are two main types of bacterial photosynthesis: oxygenic (cyanobacteria) and anoxygenic (sulfur and non-sulfur phototrophs). Molecular mechanisms of photosynthesis in the phototrophic microorganisms can differ and depend on their location and pigments in the cells. This paper describes bacteria capable of molecular oxidizing hydrogen sulfide, specifically the families Chromatiaceae and Chlorobiaceae, also known as purple and green sulfur bacteria in the process of anoxygenic photosynthesis. Further, it analyzes certain important physiological processes, especially those which are characteristic for these bacterial families. Primarily, the molecular metabolism of sulfur, which oxidizes hydrogen sulfide to elementary molecular sulfur, as well as photosynthetic processes taking place inside of cells are presented. Particular attention is paid to the description of the molecular structure of the photosynthetic apparatus in these two families of phototrophs. Moreover, some of their molecular biotechnological perspectives are discussed.

As most European forests are commercially managed for wood production, excluding the disintegration phase of the forest development cycle, a serious decline of numerous species has been observed. The intensity of forest management is critical for biodiversity conservation, especially in regard to saproxylic organisms, as it reduces the abundance of old trees and dead wood. We studied saproxylic beetles in 12 montane beech-fir stands in a Central European mountain range. We used 72 flight interception traps exposed for two vegetation seasons (2012 and 2013) placed at sites characterized by three levels of dead wood volume. In total, 7990 individuals of 287 species belonging to 41 families were collected. Species richness and abundance of both non-threatened and threatened species showed no significant differences among the three studied forest stand categories. Nevertheless, the presence of both non-threatened and threatened species in the studied forest stands was affected by several environmental variables. Large diameter dead wood, dead wood in the last decay stage and dead beech wood close to the traps significantly affected the assemblage of threatened beetles. Canopy openness, thin dead wood in the wider trap surroundings and dead wood in the second and third decay stage in the closer trap surroundings affected the assemblage of non-threatened species.

Yarns containing textile fibers and fine metal fibers in their structure are often used to produce electrically conductive fabrics. The blending quality of the fiber components in a yarn significantly affects the properties of the yarn and the produced fabric. Therefore, the arrangement of metal fibers in yarn structures needs to be analyzed, which can be done using image analysis and spatial statistics methods. One of the aims of this paper is to introduce a suitable methodology for obtaining adequate cross-sections of a yarn containing metal fibers that would allow the usage of objective image analysis methods to identify the component fibers for subsequent evaluation of spatial arrangement. In this paper, an algorithm for the objective segmentation of the component fibers in a yarn cross-section is proposed, and a methodology for evaluating the spatial arrangement of fibers using spatial statistics data is presented. The second aim is to study the specific arrangement of the fibers in hybrid yarns containing 20 wt% of a conductive component, more precisely extremely thin discrete stainless steel fibers, by the proposed methodology. Based on the results, it is concluded that the metal fibers in the cross-sections of this hybrid yarn are randomly arranged.

Although most studies exploring the vertical distribution of arthropods in forests have been limited to discrete comparisons between understorey and canopy, few have sampled across multiple heights. We studied vertical distribution of scolytine beetle flight activity in temperate lowland broadleaf and montane beech-fir forests using flight interception traps arranged in vertical transects with traps placed 0.4, 1.2, 7, 14, and 21 m above ground. In each forest type 15 vertical transects (75 traps) were used. The assemblages sampled at 0.4 and 1.2 m above ground (undergrowth) clearly differed from those at 7, 14, and 21 m (midstorey and canopy). Ambrosia-fungi feeder abundance peaked at 1.2 m in the mountains, whereas in the lowland they were almost evenly distributed from 1.2 to 21 m. Phloem feeders were significantly more abundant in the midstorey and canopy than in the undergrowth. Height preferences of eleven species were identified. Four species were associated with traps exposed at 7, 14, or 21 m, whereas seven species were associated with the height of 1.2 m. No species was associated with the 0.4 m height. To cover entire scolytine assemblages of forest stands, sampling should thus not be restricted to the usually sampled understorey level, but also cover the canopy.

Withdrawal strengths of commercially available hardwood dowels were examined in this work. Multi-grooved dowels with a straight surface pattern and with pre-glued polyvinyl acetate (PVAc) were tested. Additionally, standard dowels with different single- and multi-grooved surface patterns were also tested, which were not pre-glued. Standard dowels were bonded with two types of PVAc and one type of polyurethane (PUR) adhesive. The influence of the type of dowel, the surface pattern, the dowel diameter, and the type of adhesive used on the dowel joint strength were investigated. Lower average strengths were observed for single-grooved dowels with a spiral pattern (4.9 MPa); failures generally occurred at the first or second thread of the spiral groove. For the pre-glued dowels, there were differences in the observed strengths, which depended upon how the PVAc adhesive was activated. Lower withdrawal strengths were noted for the pre-glued dowels when they were activated by dipping them in water (3.0 MPa) versus adding water directly to the pre-drilled holes (4.7 MPa to 5.4 MPa).

Elevace přechodu mezi komplexem QRS a usekem ST na EKG křivce oznacovana jako "casna repolarizace" byla leta považovana za fyziologickou variantu normy vyskytujici se u mladých a fyzicky aktivnich jedinců. V soucasnosti roste pocet praci, ktere prokazuji souvislost tohoto fenomenu se zvýseným kardiovaskularnim rizikem. Studie u pacientů s idiopatickou fibrilaci komor (IVF) potvrdily vyssi riziko malignich komorových arytmii u osob s casnou repolarizaci. Take v běžne populaci byla elevace J bodu ve spodnich svodech spojena se zvýseným rizikem arytmicke a kardialni smrti. Předkladaný clanek rozebira soucasný stav poznani v oblasti epidemiologie, mechanismů vzniku, kardiovaskularniho rizika a pece o pacienty s casnou repolarizaci. Zaroveň upozorňuje na řadu nejasnosti, ktere budou muset být v budoucnu zodpovězeny v zajmu zlepseni predikce rizika a terapie. V neposledni řadě poukazuje na podobnosti a rozdily s ostatnimi syndromy spojenými s předcasnou repolarizaci, ať již vrozenými (syndrom Brugadových, syndrom kratkeho QT), ci ziskanými (akutni ischemie, hypotermie), ktere nově oznacujeme souhrnným nazvem "J wave syndromy".

The hitherto analyses of elastic collisions of charged nucleons involving common influence of Coulomb and hadronic scattering have been based practically on West and Yennie formula. However, this approach has been shown recently to be inadequate from experimental as well as theoretical points of view. The eikonal model enabling to determine physical characteristics in impact parameter space seems to be more pertinent. The contemporary phenomenological models admit, of course, different distributions of collision processes in the impact parameter space and cannot give any definite answer. Nevertheless, some predictions for the planned LHC energy that have been given on their basis may be useful, as well as the possibility of determining the luminosity from elastic scattering.

Elastic proton-proton collisions represent probably the greatest ensemble of available measured data, the analysis of which may provide large amount of new physical results concerning fundamental particles. It is, however, necessary to analyze first some conclusions concerning pp collisions and their interpretations differing fundamentally from our common macroscopic experience. It has been argued, e.g., that elastic hadron collisions have been more central than inelastic ones, even if any explanation of the existence of so different process, i.e., elastic and inelastic (with hundreds of secondary particles) collisions, under the same conditions has not been given until now. The given conclusion has been based on a greater number of simplifying mathematical assumptions (done already in earlier calculations), without their influence on physical interpretation being analyzed and entitled; the corresponding influence has started to be studied in the approach based on eikonal model. The possibility of peripheral interpretation of elastic collisions will be demonstrated and corresponding results summarized. The arguments will be given why no preference may be given to the mentioned centrality against the standard peripheral behaviour. The corresponding discussion of contemporary description of elastic hadronic collision in dependence on impact parameter will be summarized and the justification of some important assumptions will be considered., 24 pages, final version

International audience; Global warming and land-use change are expected to be additive threats to global diversity, to which insects contribute the highest proportion. Insects are strongly influenced by temperature but also require specific habitat resources, and thus interaction between the two factors is likely. We selected saproxylic beetles as a model group because their life cycle depends on dead wood, which is highly threatened by land use. We tested the extent to which higher temperatures compensate for the negative effects of low amounts of dead wood on saproxylic beetle species richness (Temperature–Dead wood compensation hypothesis) on both a macroclimate and a topoclimate scale (north- and south-facing slopes). We analyzed 1404 flight-interception trap catches across Europe to test for interaction effects of temperature and dead-wood amount on species richness. To experimentally test our findings from the activity trap data, we additionally reared beetles from 80 bundles of dead wood initially exposed at high and low elevations. At the topoclimate scale, we analyzed trap catches and reared beetles from dead wood exposed in 20 forest stands on south-facing and north-facing slopes in one region. On the macroscale, both temperature and dead-wood amount positively affected total and threatened species richness independently, but their interaction was significantly negative, indicating compensation. On both scales and irrespective of the method, species richness decreased with temperature decline. Our observation that increasing temperature compensates for lower amounts of dead wood has two important implications. First, managers of production forests should adapt their dead-wood enrichment strategy to site-specific temperature conditions. Second, an increase in temperature will compensate at least partially for poor habitat conditions in production forests. Such a perspective contrasts the general assumption of reinforcing impacts of global warming and habitat loss on biodiversity, but it is corroborated by recent range expansions of threatened beetle species.